Stabilized carbon tetrachloride



Patented June 9, 1936 UNITED STATES PATENT OFFICE STABILIZED CARBON TETRACHLORIDE Edmund C. Missbach, Oakland, calif assignor to Staufier ChemicalCompany, a corporation of California No Drawing. Original application October 9,

1933, Serial No. 692,819. Divided and this application January .23, 1935, Serial No. 3,183

Claims.

This invention relates to the prevention of decomposition of halogenated hydrocarbon compounds, particularly chlorinated aliphatic hydrocarbons, and to the prevention of corrosion by these compounds. It is known that these materials when exposed to moisture, light, air, and heat, particularly during distillation, as in the case of carbon tetrachloride, decompose with the formation of substances of an objectionable character, usually acidic substances which render the material unsuitable for such purposes as extractions as well as corroding equipment. The decomposition I attribute to hydrolysis and liberation of acid or acid bodies which also catalyze the decomposition.

Examples ,of materials with which the present invention is concerned are carbon tetrachloride,

C014, chloroform, CHCla, trichlorethylene, CzHCla, tetrachlorethylene, C2014, pentachloi'ethylene, C2HC15, and the like. Generally, it is concerned with chlorinated andbrominated derivatives of methane, ethane, and higher parafiins, as well as.

ethylene and higher homologues thereof.

The object of this invention is to provide an efl'ective stabilizer for chlorinated hydrocarbonswhich need be used only in relatively small concentrations.

Another object of this invention is to provide an effective corrosion inhibitor for use in the presence of halogenated hydrocarbons.

I have found that numerous compounds hereinafter set forth are effective stabilizers and corrosion inhibitors for these materials. of course, one inhibitor-may not be practical for reasons other than its corrosion inhibiting properties and choice must be exercised to the end in view. For

example, an inhibitor in carbon tetrachloride to I be used in dry cleaning clothes must not deleteriously affect fabrics to be cleaned or alter the color thereof.

7 The corrosion inhibitor used need only be present in a relatively small concentration usually a of the inhibitor being volatile with the water In cases where the solubility of the corrosion inhibitor in the halogenated hydrocarbon compound is relatively very small, it has been found that the efliciency of these particular inhibitors is so great, that only very small quantities of same are required to stabilize the halogenated hydrocarbon compound to the extent demanded in practice.

If it is desired to apply larger proportional amounts of an inhibitor of a solid type, it is reduced to a fine powder, and suspended in the halogenated hydrocarbon, which procedure is especially advisable in case of recovering -the halogenated hydrocarbon by distillation.

In some other cases, where it is desired to increase the concentration of the inhibitor above its solubility in thehalogenated compound, it is dissolved in a solvent compound miscible with the halogen compound and then incorporated. As suitable-solvents, I have used the following compounds: ethylal, methylal, n-butyl alcohol, n-

propyl alcohol, methyl ethyl ketone, allyl alcohol, allylethyl ether, methyl carbonate, ethyl carbonoil.

ate, ethyl oenanthate, beta dimethylamino-ethyl alcohol, n-heptaldehyde, and polymerized castor In the case of polymerized castor oil, this material appears to have a metal protecting action and reduces the rate of corrosion apparently by forming a protecting film on the metal.

In all cases, where the corrosion inhibitors mentioned are in the form of solid substances, or are liquids at atmospheric temperatures, and have boiling points considerably higher than that of the halogenated hydrocarbon, they are sufliciently volatile with the water vapor escaping together with the vapor of the halogenated hydrocarbon during distillation. They are therefore not only capable of protecting the latter in the liquid phase, but also in the vapor phase, 'as have'been sufiiciently demonstrated by accelerated corrosion tests made in behalf of these corrosion inhibitors, and conducted continuously fora period of 168 hours under reflux in the presence of water, as well as by use for several years under conditions met in practice with carbon tetrachloride.

This case is a division of my parent case 692,- 819 filed October 9, 1933. In this case I claim the use of aldehyde ammonia and aldehyde substituted ammonia reaction products as hexamethylene tetramine and hexamethylene amine, the aldoximes (hydroxylamine) and hydrazones (hydrazines) and more particularly aldehyde ammonia, heptaldehyde ammonia, aldehyde I class or groups, but I may also employ'ttvo or more of these substances in combination with each I 20 other, in connection with the stabilizationof :phenyi hydrozone and benzalazine which are:

useful in. stabilizing as hereinbeiore set: forth;

'particularly hexamethylenetetramine and ben-' zalazine. This. material (hexamethylene tetramine) I usually dissolve in an aldehyde as heptaldehyde or in polymerized castor, oil.

Thestabilizing effectand inhibiting action in I corrosion of my inhibitor toward decomposition of. the halogen content is, I believe, accomplished acid; thirdly, theyform a protective film on the surface of the metal, I I I I Thisinvention', however, is. not limited to the use of a single substance or compound mentioned herein, or which are related to their respective I halogenated hydrocarbons, or I may use a substance which forms a part of certain compounds I mentioned herein. I I

ize any acid or acidic substance present, and to retard the i'ormation of acid; I However, it is un- 7 solved in a solvent including polymerized .cas-

, =Strongly basic substances such as aliphatic Jing' amount of: hexamethyl'ene tetramine .dis- 2 amines, hydrazines, and hydroxylamines are here included because of their ability to neutralderstood that if: these substances produce undesirable effects, they may be used in combination I with other substances, as aldehydeae. g., form-l I aldehyde or its polymers, benzaidehyde, heptail- 'dehyde and the like, or ketones, benziLdibenzyl,

in amount of an aldehyde ammonia reaction benzoyl-acetone, or organic acids, particularly higher fatty acids, as adipic acid; abietic acid; malonic acid, palmitic acid, stearic acid, myrlstic acid, heptoic acid, nonillc acid, particularly in cases in whichthe inhibitor has a strongly basic 5 character.

The tests of materials hereinbefore set forth 5 are by way of example only, and are notto be taken aslimiting the invention whichincludes y the meet all of those compoundsdisclosed, as 10- a inhibitors for decomposition and corrosion, as I well as materials which are merelyzhigher homo- I I i logues,'or derivatives; or substitution products of the disclosed inhibiting compounds. By stabil- I izingamount I mean a quantity less than about 15 1% :and capable oi stabilizing andpreventing decomposition of the C014,. I Iclaim: a "1'. Carbon tetrachloride containing a stabiliz- 1 product.

a I 2. Carbon tetrachloride containing a stabili zing amount of hexamethylene tetramine. I I I 3..Carbon tetrachloride containing a stabiliz-' solved in asolvent.- 7

4. Carbon tetrachloride containing a stabiliz ing. amount of zhexamethylenetetraminedis I '5. Carbon 0.16%;hexamethylene tetramine. I

51 i I I EDMUND,C.MISSBACH.

tetrachloride containing about I 

